docs: def _format_arg_list(args, variadic=False):
      """Format a list of arguments for pretty printing.
  
      :param a: list of arguments.
      :type a: list
  
      :param v: tell if the function accepts variadic arguments
      :type v: bool
      """
      def sugar(s):
          """Shorten strings that are too long for decency."""
          s = s.replace("{", "{{").replace("}", "}}")
          if len(s) > 50:
              return s[:20] + " ... " + s[-20:]
          else:
              return s
  
      def arg_to_str(arg):
          """Convert argument to a string."""
          if isinstance(arg, str):
              return sugar(repr(arg))
          elif arg is Parameter.empty:
              return '\u2014'
          else:
              return sugar(str(arg))
  
      if not args:
          if variadic:
              return "(\u2026)"
          else:
              return "()"
  
      return "(" + ", ".join(map(arg_to_str, args)) + ")"